The checkpoint that the attacker passed through seems to be the most vulnerable part of the complex. Trees create distance for the main building of the embassy, but that side entrance is exposed to a street — making it susceptible to a bomb attack.

The bombing killed a member of the embassy's Turkish staff and the bomber. There was no damage inside the embassy.

There are U.S. personnel placed on rooftops around the perimeter, and these men may be in boxers since Marines work in shifts and were told get up there ASAP to stand guard for potential future attacks.

The first level of embassy security — the outside — is usually covered by the host nation while the inside is covered by Marines and diplomatic security from the state department.

Here's the full video from A HABER.

No party claimed responsibility for the attack, but Kurdish rebels and Islamic militants are active in Turkey while the country has also been deeply affected by the brutal civil war in neighboring Syria.

The State Department has advised American citizens to not visit the Consulates in Istanbul, Adana or the Embassy in Ankara "until further notice."